6307-NTN bearing: complete specifications & equivalents

Specification table

Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)) · extracted 2026-09-25

Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.

Cross references & equivalents

Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.

How the 6307-NTN model number is decoded

In the 6300-series (diameter series 3 of ISO 15) the last two digits encode the bore: 6307 carries bore code 07 = 35 mm. Outside diameter 80 mm and width 21 mm come from the ISO 15 boundary-dimensions general plan. With no seal suffix the bearing is open: no shields or seals are fitted and lubrication is supplied by the application. For normal-load mounting with a rotating inner ring on a 35 mm shaft, typical catalogue practice is a k5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. In the NTN catalogue this open execution carries the bare designation; protected variants are ordered separately with suffixes ZZ (shields), LLB/LLF (non-contact seals), LLH (low-torque contact seal) and LLU (contact seal).

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Sizes around 35 mm bore are normally pressed on cold with a sleeve against the inner-ring face; the press force must never route through the outer ring or the balls of 6307-NTN.
• The 63xx medium section at 35 mm bore gains dynamic rating through larger rolling elements on a 80 mm OD; the penalty is mass and a lower limiting speed than the 6207 — do not specify it for speed-critical shafts.
• The open 6307-NTN has no lubricant retention: grease escapes and contaminants migrate straight into the 35×80×21 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
• Storage matters for open bearings: 6307-NTN leaves the factory with rust preventive only, so clean it and apply the service grease at assembly even if the rings look oily from the wrapper.
• Shaft and housing fillets must clear the bearing chamfer so the 21 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
• Measure the shaft, do not trust the drawing: a 35 mm nominal journal worn by even 0.02 mm turns an interference seat into a creeping fit that frets the bore of 6307-NTN.
• The open 6307 has no integral sealing; in the NTN 2203 catalogue the protected variants carry suffixes ZZ (non-contact steel shields), LLB/LLF (non-contact rubber seals), LLU (contact rubber seals) and LLH (a low-torque contact seal with higher speed capability than LLU). A JR or JRX suffix (printed for some thin-section sizes) denotes a pressed-steel cage, not a seal.
• The 35 mm bore puts 6307 in NTN's general-purpose industrial range; the standard pressed-steel cage and CN clearance cover most electric-motor and pump duty, but for continuous high-speed use specify the LLH low-torque seal (not LLU) and confirm the housing allows the listed limiting speed.
• At 8800 r/min the grease limiting speed for 6307 covers most general-purpose industrial drives; the open or shielded execution can run continuously at this speed with standard lithium-soap grease.
• NTN rates 6307 at 37 kN dynamic (C) and 19.1 kN static (C0), 1.47 kN fatigue load limit Cu; this upper-medium rating covers conveyor and gearbox drives, but at these loads the pressed-steel cage can be the limiting factor under shock — consider the machined brass cage (suffix M) for impact duty.
• At 457 g, 6307 requires a soft-jaw vise or arbor press for mounting — never hammer it onto the shaft, and support the opposite ring to avoid brinelling the raceways.
• The 35×80×21 mm envelope of 6307 gives a D/d ratio of 2.29 and 22.5 mm radial section height — a heavy section built for high-load, lower-speed duty; specifying it in a high-rpm motor generates excess heat and shortens grease life, so prefer a 62/63-series there.
• The 37/19.1 kN load ratings, 1.47 kN fatigue load limit Cu NTN lists the grease limiting speed at 8800 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 457 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6307 on the 35×80×21 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 6307 in a rated drive.
• Two NTN bearings of the same designation from different production lots can carry minor internal-geometry revisions; for paired or preloaded arrangements on one shaft, order a single lot through the NTN distributor.
• NTN date-codes its packaging; rotate stock first-in-first-out, because the grease inside sealed units ages on the shelf — after three to five years of storage, check the grease condition before putting the bearing into service.